Because domestic networks include a plurality of Internet Service Providers (ISPs), packet loss or delay often occurs in network access, particularly in cross-ISP access, which causes a failure in users browsing a website. Meanwhile, various security devices (for example, firewalls, Web Application Firewall) in the networks may also mistakenly intercept normal requests. These problems have a negative effect on website access experience and thus reduce a service quality of website access.
Existing content delivery network (CDN) products may generally adopt a back-to-source retry to solve the problem that node access to a source website is unavailable, which has certain effects in the event that the network is temporarily interrupted, but has no effect in the event that the network is blocked for a long time or intercepted by the security devices.
In traditional CDN systems, each node only has one path to access the source website, and thus failure of browsing requests from the users may occur when the path is blocked.